The user interface on this plug-in is decidedly non-standard. The checkbox "enable particle" is not a global setting for all effects. Instead, you must first choose each effect from the Type listbox (dust, flicker, hair, etc.). Once selected, go back up to the Enable Particles checkbox and either enable or disable this specific effect. Once you've done that, you then need to use the Amount slider to control the degree of effect you want.

The effects are not subtle -- in fact, just the opposite. They are pretty severe and generally a little goes a long way. If you aren't seeing anything, then this is probably the reason.